However, selection may depend on factors beyond the studied game, which on average should represent equal contributions to each individual's fitness, irrespective of their strategy. To account for this, we use the fitness formulation proposed in [1]}, which includes a parameter representing the intensity of selection \(w\in [0,1]\) :
\(f_i^N= 1-w+w \frac{a (i-1)+b (N-i)}{N-1},\) 
\(g_i^N = 1-w+w \frac{c i + d (N-i-1)}{N-1}.\) 
